


Assumptions

by GideonGraystairs



Series: Love Finds A Way [2]
Category: Shadowhunters (TV), The Mortal Instruments Series - Cassandra Clare
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Different First Meeting, Coming Out, Developing Relationship, Friends to Lovers, M/M, Magnus Bane Is Quite Magical, Post-Canon, Supportive Magnus Bane
Language: English
Status: Completed
Published: 2021-01-27
Updated: 2021-01-27
Packaged: 2021-03-13 11:48:46
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,318
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29028225
Author URL: https://archiveofourown.org/users/GideonGraystairs/pseuds/GideonGraystairs
Summary: Now that he knew a little better who Alec was outside of his Shadowhunter duties, it was difficult not to stare. All these years and he’d barely spared Alec a thought, easily dismissed as just another Nephilim. Three years of monthly, if not weekly, meetings and he’d never taken the time to just...lookat Alec.And now he couldn’t stop.An AU where Magnus doesn't meet Alec until after he marries Lydia, and doesn't start get to know him until after they divorce.
Relationships: Lydia Branwell & Alec Lightwood, Magnus Bane/Alec Lightwood
Series: Love Finds A Way [2]
Series URL: https://archiveofourown.org/series/2120097
Comments: 30
Kudos: 179





	Assumptions

**Author's Note:**

> This could probably be read as stand-alone, but it makes more sense if you read Expectations first. Assumptions picks up exactly where it left off.

Alexander Gideon Lightwood, Shadowhunter and head of the New York Institute, was without a doubt one of the most unexpected things Magnus had encountered in all his long years. Every time he started to think that he had him figured out, Alec went and did something that blew up everything he’d thought of him.

It was like Alec lived to keep Magnus on his toes. That was what he got for making hasty judgments of character, he supposed. 

Like tonight, for example. Here Magnus was, thinking Alec was finally showing the true colours of a Shadowhunter. It was rare that he met one that wasn’t prejudiced. He supposed it was difficult not to be, living your whole life embedded in a culture that demonized anything they didn’t understand.

And here Alec was, the furthest from it you could get.

Magnus shook his head. What a wonder this unassuming little nephilim had turned out to be.

“Another round?” Magnus suggested. He kept any expectation out of it, not certain how much Alec’s confession may have shaken him. Alec had tried very hard to communicate his sexuality without saying the words, and Magnus felt a little guilty that in the end he’d still had to. He wondered, briefly, if perhaps this was the first time he’d confessed such a thing. But then, Alec had been married, and his siblings seemed like the intrusive kind.

He watched Alec shake himself, as though coming out of deep thought. “Yeah, sure.”

Not for the first time, Magnus found himself wondering what was going on inside that head of his.

For as long as Magnus had known him, Alec had been a source of confusion. Jace and Isabelle’s elusive older brother, too caught up in smoothing over the consequences of their adventures to join them. The eldest Lightwood, youngest Shadowhunter appointed head of an Institute, in spite of the mud his family name had been dragged through with the Circle’s return. The first high ranking Shadowhunter to reach out to the Downworld with an open ear and no agenda but to see that the bad blood between them be put to rest, as much as one man could promise.

If he was being honest, Magnus had doubted him for a while. Years, even. He couldn’t count the number of cabinet meetings he’d sat through, waiting for the other shoe to drop, certain it was coming.

_Surely_ Alec had inherited the prejudices of his people and, surely, they would be reflected in the legislature he passed. Magnus had heard pretty words from Nephilim before when they were facing a war they couldn’t win, and they had taken them to their laws and twisted them up into the discrimination that lived on in the form of the Accords. That was the main point of focus for the cabinet: rewriting the Accords, or doing away with them altogether. 

That had been the first surprise, Magnus mused. The discovery, slowly but surely, that Alec actually took their concerns to heart and worked hard to see them rectified. Magnus couldn’t help but respect him. Even more so when his willingness to see Alec’s sincerity made it possible to see his drive. He started to pay more attention when Alec showed up to the cabinet empty-handed, the Clave having declined all their requests — a regular occurrence. He could see that Alec was just as frustrated as they were and, right behind it, how determined he was to try again. Sometimes Magnus thought he fought harder for the Downworld than they did.

Still, Alec had remained a mystery. He was so _disciplined_ at each meeting, his handshake firm and formal and his posture in parade rest more often than not. He had a laser-focus on Downworld-Shadowhunter relations and never spoke about himself or his personal life. He was a difficult man to get to know, and even more so to understand.

If he hadn’t been privy to some of Isabelle’s scathing off-hand remarks around the time of his wedding, Magnus might not have even known that he was married. And then, of course, he’d had no idea what kind of marriage it was. 

Another surprise. He’d assumed Alec and Lydia were in love. That was how Shadowhunters worked, wasn’t it? One all-consuming, undying love to last their often short lives. That had been the justification for outlawing divorce, if he recalled correctly. Thank God they’d gone back on that only a few short decades ago, if only for Alec’s sake.

It was the biggest shock to the image Magnus had in his mind of Alec — that night, finding the Shadowhunter wallowing at the Hunter’s moon, confessing to a near stranger that his marriage had been a sham.

Maybe that wasn’t fair. It didn’t sound like it’d been a mad marriage. Alec certainly wasn’t resentful, and the way he spoke about her made it clear that they loved each other as much as any married couple would.

But what a shock it was, to find out it wasn’t romantic. Alec and Lydia had certainly seemed like the ideal Shadowhunter couple. He knew they ran the Institute together. He’d seen the well-oiled machine it had become since they’d taken over. And Alec had smiled, an unusual sight, the few times her name had come up in their meetings. They were the perfect partners, in all the work they did.

With what he knew now, Magnus thought he could piece together the more intimate picture. 

Magnus felt foolish looking back on it now. He remembered hearing about their impending wedding through the rag tag group of Shadowhunters that simply wouldn’t leave him alone. ( _Magnus, portal me! Magnus, summon a memory demon for me! Magnus, save me from my own stupidity!_ ) Isabelle’s frustration made more sense to him now, if she’d known about Alec. At the time, he’d thought Lydia must have been an actual devil to warrant such harsh words. Even Jace had had nothing nice to say about it, and Magnus had always thought him the type to smack his brother on the back and congratulate him for scoring such a knockout.

Perhaps it would do Magnus well to stop assuming anything about Alec and his personal life — so far, he had been wrong one hundred percent of the time. After Alec’s first post-divorce, drunk confession, Magnus probably should have learned to stop trying to squeeze Alec into the Shadowhunter-shaped box he’d built over the centuries. He was beginning to think he should do away with the box all together, the fonder he grew of that rag tag group still stirring up trouble at the Institute.

Magnus tried to cast all of his judgements aside as he watched Alec take a swig of his drink and then promptly wrinkle his nose, frowning at it. He huffed out a quiet laugh — how many times had he come and still Alec had only one drink at the Hunter’s Moon that he actually liked.

Chalking the end of his cue stick, Magnus assessed the situation. After a moment’s contemplation, he took his shot: he sunk both the six and nine. There was one striped ball left on the table to the three solid.

Alec looked impressed. “Alright,” he conceded. “Not bad. Though I’d like to point out you’ve had centuries to practice.”

Magnus gave him a look of feigned concern. “When do you think this game was invented, Alexander? More importantly, how old do you think I am?”

It drew a laugh out of Alec, which drew one out of Magnus, too. “Actually,” Magnus continued, off the weird need he had to hear that laugh another time. “I have a wonderful story about this time I played billiards with the queen of England.”

When Alec looked at him with interest, Magnus launched into the story. As he’d hoped, it did make Alec laugh, but it also left a wider smile on his face than Magnus had ever seen. It was so far from the Alec he had grown accustomed to these past few years. He was almost certain he could count the times he’d seen Alec smile on both hands, no extra fingers needed.

As the night progressed, Magnus found himself dropping his guard as well. He took all of his pretenses about Shadowhunters and Lightwoods and set them gently to the side. Never had he expected it would be so easy to laugh with Alexander Lightwood. Magnus hadn’t felt his smile muscles ache like this in quite a while.

_A surprise_ , he thought to himself, as he watched Alec lean down to take his shot at the ball. A couple strands of black hair fell into his eyes, and Magnus had the strangest urge to brush them behind his ear. _What a delightful surprise, indeed_.

.

Now that he knew a little better who Alec was outside of his Shadowhunter duties, it was difficult not to stare. All these years and he’d barely spared Alec a thought, easily dismissed as just another Nephilim. Three years of monthly, if not weekly, meetings and he’d never taken the time to just... _look_ at Alec.

And now he couldn’t stop. Alec wasn’t even talking. It was Luke who was waving a hand around to punctuate his dissatisfaction with how the werewolf territorial dispute was being handled. Magnus tried to listen, he did, but his attention kept drifting to the Shadowhunter who was nodding grimly along.

He was still having trouble reconciling this Alec with the Alec that had accidentally become his drinking buddy. 

“Magnus?” Alec interrupted his thoughts. He had an eyebrow raised in question, and when Magnus looked around the table, it was obvious this wasn’t the first time they’d tried to get his attention.

He shook his head and straightened, fixing his jacket. “Sorry. I must’ve gotten lost in my thoughts for a moment.”

“It’s fine,” Alec replied, but he continued to look at Magnus oddly. “Luke was just asking if you’d heard from Catarina about the… cubs she was healing.”

Alec’s awkwardness at using Downworlder slang was sweet, but Magnus tried not to focus on it. Instead, he reigned himself in, collected his thoughts, and went as deeply into High Warlock mode as he’d ever been. “They’re well,” he said. “Returned to their pack already. I doubt they’ll be so lucky next time.”

Luke shook his head, all tense muscles. “This can’t go on like this. The next time they go at it, there _will_ be deaths. Both alphas have made that very clear.”

Alec huffed out a heavy breath, rubbing his forehead. “There has to be a way to divide the territory that they’ll both accept. How have they been living peacefully, side by side, for so many years without it being an issue?”

“It’s not about the territory,” Luke replied. “It’s about their pride. Karr’s pissed his daughter joined Matt’s pack when she married his son, and Matthew’s taking it as an insult, like he thinks she’s too good for them. But how do you rally your whole pack around a petty grudge? You make it out to be something it isn’t, something that affects them.”

Alec nodded in understanding. “The territory.”

Raphael, who’d spent most of the meeting watching them in total boredom, snorted. “Werewolves. Uncivilized animals.”

“Vampires,” Luke snapped. “Pretentious butchers. How many has your clan killed this year?”

Magnus interjected, waving a hand in the air. “Children, children. Let’s not fight. We’re meant to be finding a solution, not exemplifying the problem. I, for one, suggest we tell them neither gets the land until they kiss and make up and stop sending poor, defenseless little cubs out to do their dirty work.”

“They are still _werewolves_ ,” Alec punctuated. “I wouldn’t call them defenseless. Both sides roughed each other up pretty good, didn’t they?”

Magnus waved him off. Alec gave a little shake of his head as though to say _you’re absurd_. 

They were both drawn back to the issue by Luke. “Magnus has a point, actually. If they can’t agree to share it like they always have, maybe it should be property of the Downworld council until they change their minds.”

Raphael scoffed. “And what makes you think they won’t hold a grudge against us, too? I don’t want angry wolves showing up at the Du Mort.”

“I’ll draw up the paperwork and give it to them myself,” Alec offered. “No one else needs to be involved. If they have a problem, I doubt they’d be stupid enough to come knocking on the doors of the Institute.”

Everyone mumbled their agreement. With the matter apparently settled, it was mutually understood that the meeting was over. Raphael nodded goodbye exclusively to Magnus and made his departure, but Luke stuck around for longer.

Normally, Magnus would have also bid his farewells and made a grand exit. Today, he had yet to even stand from his seat. As Luke approached Alec, drawing his attention away from the papers he was carefully gathering and sorting, Magnus wondered if maybe they’d just assumed he’d left anyway and didn’t realize he was there.

“Hey,” Luke said, only a foot away from Alec. His voice was quiet, his face contrite. “I heard about Lydia. I’m sorry. I’m sure your family’s got it covered, but if you need anything, I’m here too.”

“Thank you, Luke. But I’m fine.” Alec’s body language didn’t change. He remained composed, his smile polite, nothing that gave away whether he was upset, caught off guard, or the slightest bit uncomfortable. 

It was telling, Magnus thought, of how good Alec was at maintaining the façade of the perfect delegate, the perfect, unshakable soldier. Magnus prided himself on being exceptionally perceptive — that tended to happen when you had centuries to learn how to read the world around you — but even with the knowledge of what Alec’s marriage looked like behind the scenes, Alec was unreadable.

“That’s good,” Luke said, in a way that implied he didn’t believe him. A little too gentle, sympathetic. Almost patronizing. “Still, I’m here.”

With that, he patted Alec on the shoulder and left. Alec watched after him with a neutral expression until his foot crossed the threshold, and then frowned. Magnus looked at him for a moment longer before he decided to say something.

“I suppose the gossip is running its course, then,” he offered. Alec blinked at him. As Magnus had thought, he’d forgotten he was there.

After a moment, Alec sighed. He sank back down into his chair across the table from Magnus, abandoning the collection of his notes. All he said was a very heavy, “Yeah.”

Magnus hummed sympathetically. He thought perhaps he should say something to comfort him, to reassure him that everyone would lose interest in the gossip once the novelty died down. Or perhaps he should say something humorous to lighten the air. If he’d known Alec as little as he had two months ago, he would have.

Now, he took a moment to think a bit harder.

“How are you doing, really?” he asked, in a neutral tone.

Alec stopped rubbing his forehead, slumped down in his chair. He met Magnus’s eyes, and Magnus could see him contemplating his answer. He looked away before he spoke. “Good, I think. It’s… Not really any different, actually. Lydia is still living here, and she isn’t stepping down from running the Institute with me. She’s going back and forth more to Alicante to see her family. It’s just… Strange, I guess. Because nothing has changed, but it still feels like everything has.”

Magnus watched Alec frowning down at the floor with a conflicted expression. “It must be comforting, to have such a partner. I’m sure it’s discomfiting to think that that partnership doesn’t mean the same as it did, but you haven’t really lost anything, Alec. I think it’s abundantly clear that Lydia isn’t going anywhere. But what you’ve gained? You have the chance to let someone else in too, now. I know you love her fiercely, but wouldn’t you like to know what it’s like to be with someone you _want_ just as much as you love?”

Alec was silent for long enough that Magnus wondered if he had over-stepped. He wondered each time he tried to comment on Alec’s relationship — he had from the first night Alec had spoken to him about it. It felt like he was intruding on something intimate, like there was Alec-And-Lydia and he was an outsider with the gall to act like he knew anything about them.

But he thought he was beginning to. He was no Lydia, or Isabelle, or whoever else Alec must share the details of his life with, but he felt like he’d been privy to a side of Alec that neither of them were.

_There’s just certain ways they expect a Shadowhunter to be_ , Alec had told him. It must’ve been painful to meet those expectations, and Alec didn’t strike him as the kind of person to share that pain with the people he loved, especially when they wouldn’t have understood.

“Maybe,” Alec said, finally. He didn’t look convinced.

.

Magnus twisted his phone around in his hands, worrying his lip. The party was only just beginning — his warlock friends and a small gaggle of werewolves currently the only guests — but he scanned the room to make sure everything was still perfect. He’d used his magic to transform the loft into a place fit for dancing, flashing lights of different colours and enough seating for the wasted to avoid making a scene.

He glanced at Catarina, inspecting the dessert tower. Then the door, where a steady stream of people was coming through. He hesitated only for one more second before he turned on his phone’s screen, banishing any uncertainty he felt.

Alec picked up on the second ring. “Magnus?” he sounded confused. Probably because it was nearly midnight, and they usually texted instead of calling if they felt like getting overly competitive in a game of pool.

“ _Alexander_ ,” Magnus said, wonderfully. “I’m so glad you answered. I’m having a get together, come over.”

There was a very long pause. “I… What? What kind of get together? A party?”

“The fun kind, of course, but no, not a party. If you’re worried about being the only Shadowhunter in a room full of Downworlders, don’t be. I’m sure your lovely sister will sneak her way in somehow. She usually does, though I pretend not to notice. Let her find a nice seelie to take home, if she likes.”

“You’re inviting me to a party?” Alec sounded incredulous. “ _Me_?”

Magnus softened, dropping some of the grandeur. “Alec,” he said. “It’ll be fun. And you can put yourself out there and not have to worry about word getting around to anyone you don’t want it to, I promise.”

When Alec didn’t answer, Magnus backtracked. “But that’s entirely not my place! Do whatever you want, whenever you’re ready. But _please_ come to my party. I made some magic, Russian roulette-style cocktails. The result is hilarious.”

There was another long silence. Then, “I thought you said it wasn’t a party.”

Magnus smiled. “I’ll see you soon.”

.

At another cabinet meeting to address the werewolf problem that had only grown more irritating, Alec rolled his eyes at Magnus from across the table while Raphael and Luke went back and forth. Magnus laughed, then put a hand up to his mouth to stifle it. The others paused to frown at him, then continued the dispute.

When he looked back at Alec, he appeared very pleased with himself.

Again, Luke snapped them both out of it. “Great, it’s settled then. Anyone have anything else they’d like to share?” He was looking very pointedly at Alec, who only frowned at him. Luke pursed his lips. “Clary mentioned one of your trainees is missing.”

Alec huffed. He looked away, around the table at the circle of Downworlders watching him. “It’s nothing. He just had his Rune Ceremony and was frustrated we weren’t sending him out on missions anytime soon. He’ll be back. Nothing any of you need to worry about.”

His tone was too tight for it not to seem like it was a bigger deal than he was making it out to be, but the _‘this is a Shadowhunter issue and it’s none of your concern’_ was heavily implied. Luke watched him for a moment longer, considering, before he let it go. “That’s good,” he offered. “I guess we’re done, then?”

A rumble of agreement sounded around the table, and everyone made their way out. Alec left quickly this time, so Magnus had no reason to linger.

Raphael caught him just as he was leaving, pulling him aside into a secluded hallway. His brows were knit together, his face tight. “You’re friends now?” he asked. “With Alec?”

Unsure where this was going, Magnus hesitantly replied, “I suppose?”

Raphael stared at him for a long moment. That brooding, serious special vampire stare. He was still holding Magnus’s arm. “He’s a _Shadowhunter_ ,” Raphael told him like it had some disguised meaning. “Be careful.”

Magnus snorted. “Relax. It’s not like we have sleepovers and braid each others’ hair, we’re really not that close. He’s just a pretty good pool buddy and, also, if you forgot, a good person to talk politics with.”

“Right,” Raphael nodded, but he was still eyeing him suspiciously. “Keep it that way. You don’t want to get too invested in someone who could turn around and screw the Downworld at any time, if the Clave asked him to.”

Magnus frowned. He thought to defend Alec, but took too long. Raphael had left. He was right, anyway. Alec was a dutiful soldier before he was anything else. But, still, Magnus liked to think he had enough of a conscience to not just blindly follow every order he was given.

.

_Well, then_ , Magnus thought to himself, standing in his living room. Light poured through the window, tinted pink with the rising sun. _I suppose we’ve been here before._

He considered waking Alec, whose long legs were sprawled across his couch, but thought better of it. Instead, he quietly made his way to his workshop. He couldn’t stop the smile on his face as he brewed the familiar potion. Only three months ago, he’d made the very same one for the very same Shadowhunter snoozing away in his living room. At the time, he’d paused before adding each ingredient, second guessing if his efforts would be appreciated or if Alec would turn out to be an asshole when he wasn’t drunk and devastated. Now, he merrily plucked things off shelves and cast them into the cauldron, humming to himself. How things had changed.

As though to highlight how different this morning was to the last one, Alec woke before he was done. So absorbed in the rhythm of his magic, Magnus didn’t notice him until there was a bleary-eyed Shadowhunter in the doorway, staring at the sparks coming off his hands.

He felt himself warm at the sight. Alec’s hair was a mess, his eyes were unfocused and red, and the couch had left a red imprint on the side of his face. Not to mention the look on his face — spaced out, confused, and still trying to shake off the sleep. It was a better look without the red eyes from crying that’d been there last time. It was adorable.

Magnus let the thought pass. He smiled brightly, putting the cork back on his bottle of vampire hair. “Good morning! Did you sleep well?”

Alec gave him a flat look. “No,” he replied. “Why did you want to get drunk, again?”

Unbothered by the unenthusiastic response, Magnus summoned his favourite set of teacups with a swish of his fingers. “To get over my devastation at Malcolm not inviting me to his birthday party. Honestly, who does he think he is? What kind of—”

“—party is it without you, High Warlock and esteemed socialite. He should be so lucky as to be graced with your presence,” Alec finished for him, yawning. 

Magnus grinned, holding the cup of magic hangover cure out to him. “Exactly.”

Alec rolled his eyes, but Magnus could see the corners of his mouth twitching up when he walked across the room to accept the drink. He braced himself with all the training of a soldier, then took a massive gulp. Immediately shaking his head, he moved his jaw around like he was trying to banish the taste. His eyes drifted over the litany of beakers and bottles spread over the table.

“I _really_ don’t want to know what’s in this, do I?”

“No,” Magnus confirmed. “Definitely not. Works wonders, doesn’t it?”

“It’s magical,” Alec said, with absolutely no inflection. 

It took him a second, but Magnus laughed. The more time he spent with him, the more Alec’s dry sense of humour came out. It caught him off guard, most times, but each time it summoned an odd feeling inside of him. This need to get to know Alec more, and this appreciation for how much he already had.

He’d put aside every assumption he’d ever made about Alexander, and in doing so had discovered just how special Alec was. He was so unlike any Shadowhunter Magnus had ever known. But Magnus was beginning to accept that it was more than that — he’d disarmed Magnus so thoroughly that he was unlocking something in him that he hadn’t felt in over a century. He wasn’t sure whether it would be best to let it continue, or to slam the doors and throw his guards up again.

Magnus shook his head. He couldn’t keep the fondness from showing as he said, “You should feel special. I don’t make this for just anyone, you know.”

Alec paused, the cup halfway to his mouth. He met Magnus’s eyes. “What about last time, then? You barely knew me.”

Magnus didn’t look away. “As I said. You should feel special, Alexander.”

**Author's Note:**

> Thank you for reading, I hope you enjoyed <3
> 
> A massive massive thanks to [jeanboulet](jeanboulet.tumblr.com) for beta-ing this one, too!
> 
> I have a few more in this series already written, one of which is fully edited and beta'd, so expect more soon. And again, if there's anything you're curious about in this verse or want to see, feel free to tell me!


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